When times get tough, even Walmart's "everyday low prices" aren't all that alluring to shoppers -- except when it comes to food. We all have to eat, and Walmart's latest push could make it an even more dominant force in the grocery business.

Here are a few things that will shape this week on Wall Street: Apple should make some news at its Worldwide Developers Conference; Elsewhere, look to earnings reports from Zumba maker Majesco, retailer Pier 1, supermarket chain Kroger, and luxury brand Kors.

Memo to extreme couponers: Some retailers, particularly supermarkets and drugstore chains, are mad as hell and they're not going to take it anymore. To save their bottom lines, they're setting limits on just how much all your coupon cleverness can save you.

Whole Foods is asking its shoppers to help a good cause -- with "LIFE Jackets." They're reusable cup sleeves to protect your hands from hot beverages, and all proceeds go to Kenyan women and special-needs children.